US2417038A - Fluorescent material - Google Patents

Fluorescent material Download PDF

Info

Publication number
US2417038A
US2417038A US560344A US56034444A US2417038A US 2417038 A US2417038 A US 2417038A US 560344 A US560344 A US 560344A US 56034444 A US56034444 A US 56034444A US 2417038 A US2417038 A US 2417038A
Authority
US
United States
Prior art keywords
potassium chloride
thallium
fluorescent
fluorescent material
calcium phosphate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US560344A
Inventor
Richard H Clapp
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GTE Sylvania Inc
Original Assignee
Sylvania Electric Products Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sylvania Electric Products Inc filed Critical Sylvania Electric Products Inc
Priority to US560344A priority Critical patent/US2417038A/en
Application granted granted Critical
Publication of US2417038A publication Critical patent/US2417038A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/62—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing gallium, indium or thallium
    • C09K11/626—Halogenides
    • C09K11/628—Halogenides with alkali or alkaline earth metals
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/70—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus
    • C09K11/72—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus also containing halogen, e.g. halophosphates
    • C09K11/73—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus also containing halogen, e.g. halophosphates also containing alkaline earth metals

Definitions

  • This invention relates to luminescent materials, and particularly to luminescent materials which emit ultraviolet radiations of erythemal and therapeutic wavelengths.
  • An object of the invention is to produce a luminescent or fluorescent material which emits radiation in the neighborhood of 3000 Angstrom units in response to excitation by shorter wavelengths, and a further object is to produce such a material with a reasonable life, even in the presence of electrically excited mercury atoms.
  • a feature of the invention is the use of a fluorescent material containing both calcium phosphate and potassium chloride, with thallium activation. If we take as 100 the radiation in the 3000 Angstrom region of thallium-activated potassium chloride alone, the radiation from thallium-activated calcium phosphate alone in that region will also be found to be 80. But a fired mixture of these two thallium-activated materials forms a fluorescent material with a radiation of 200, or twice as much as can be ob-' tained from either component separately. Moreover, while the potassium chloridematerial or phosphor turns black and loses its fluorescent power after a few hours operation on the inside of a fluorescent lamp using an electrical discharge in mercury, my new material has a longer life under such conditions. The potassium chloride phosphor alone is hydroscopic, and difficult to use with ordinary coating processes, but my new material overcomes this difficulty.
  • I may mix finely powdered tri-calcium phosphate, potassium chloride, and thallium sulphate, ball-milling in acetone to secure intimate contact between the particles.
  • the powdered mixture is then filtered, and dried, after which it is fired for one or two hours at about 900 C. to make the combination fluorescent, and is then re-milled.
  • thallium sulphate is used in the mixture as an activator.
  • the properties of the resultant material change minishes somewhat as small percentages of potassium chloride are used, and the material loses its fluorescent property altogether where 10% to 15% potassium chloride is used.
  • the ultraviolet emission drops from with no potassium chloride to zero with 10% potassium chloride. With larger proportions of chloride, the ultraviolet fluorescence again returns, reaching a value of 200 with between 25% and 50% chloride. Above 50%, the fluorescence again drops, becoming again when 100% potassium chloride and no calcium phosphate is used.
  • the material may be used as a coating on the inner surface of the glass wall of fluorescent lamp tubes usual in the art, if desired.
  • the lamp will then emit radiation in the 2900 to 3100 Angstrom unit range, and be effective for tanning and therapeutic purposes.
  • a luminescent material consisting essentially of a fired mixture of calcium phosphate and potassium chloride, thallium-activated, the potassium chloride being between 25% and 50% of the composition by weight.
  • a luminescent material consisting essentially of a fired mixture of calcium phosphate, potassium chloride and thallium sulphate, the potassium chloride being between 25% and 50% of the composition by Weight and the thallium sulphate being about 3% by weight.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Luminescent Compositions (AREA)

Description

Patented Mar. 4, 1947 FLUORESCENT MATERIAL Richard H. Clapp, Danvers, Mass, assignor to Sylvania Electric Products Inc., Salem, Mass, a corporation of Massachusetts No Drawing. Application October 25, 1944, Serial No. 560,344
2 Claims.
This invention relates to luminescent materials, and particularly to luminescent materials which emit ultraviolet radiations of erythemal and therapeutic wavelengths.
An object of the invention is to produce a luminescent or fluorescent material which emits radiation in the neighborhood of 3000 Angstrom units in response to excitation by shorter wavelengths, and a further object is to produce such a material with a reasonable life, even in the presence of electrically excited mercury atoms.
A feature of the invention is the use of a fluorescent material containing both calcium phosphate and potassium chloride, with thallium activation. If we take as 100 the radiation in the 3000 Angstrom region of thallium-activated potassium chloride alone, the radiation from thallium-activated calcium phosphate alone in that region will also be found to be 80. But a fired mixture of these two thallium-activated materials forms a fluorescent material with a radiation of 200, or twice as much as can be ob-' tained from either component separately. Moreover, while the potassium chloridematerial or phosphor turns black and loses its fluorescent power after a few hours operation on the inside of a fluorescent lamp using an electrical discharge in mercury, my new material has a longer life under such conditions. The potassium chloride phosphor alone is hydroscopic, and difficult to use with ordinary coating processes, but my new material overcomes this difficulty.
In carrying out my invention, I may mix finely powdered tri-calcium phosphate, potassium chloride, and thallium sulphate, ball-milling in acetone to secure intimate contact between the particles. The powdered mixture is then filtered, and dried, after which it is fired for one or two hours at about 900 C. to make the combination fluorescent, and is then re-milled.
Generally about 3% by weight of thallium sulphate is used in the mixture as an activator.
The properties of the resultant material change minishes somewhat as small percentages of potassium chloride are used, and the material loses its fluorescent property altogether where 10% to 15% potassium chloride is used. The ultraviolet emission drops from with no potassium chloride to zero with 10% potassium chloride. With larger proportions of chloride, the ultraviolet fluorescence again returns, reaching a value of 200 with between 25% and 50% chloride. Above 50%, the fluorescence again drops, becoming again when 100% potassium chloride and no calcium phosphate is used.
The material may be used as a coating on the inner surface of the glass wall of fluorescent lamp tubes usual in the art, if desired. The lamp will then emit radiation in the 2900 to 3100 Angstrom unit range, and be effective for tanning and therapeutic purposes.
What I claim is:
1. A luminescent material consisting essentially of a fired mixture of calcium phosphate and potassium chloride, thallium-activated, the potassium chloride being between 25% and 50% of the composition by weight.
2. A luminescent material consisting essentially of a fired mixture of calcium phosphate, potassium chloride and thallium sulphate, the potassium chloride being between 25% and 50% of the composition by Weight and the thallium sulphate being about 3% by weight.
RICHARD H. CLAPP.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS German Feb. 26, 1941
US560344A 1944-10-25 1944-10-25 Fluorescent material Expired - Lifetime US2417038A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US560344A US2417038A (en) 1944-10-25 1944-10-25 Fluorescent material

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US560344A US2417038A (en) 1944-10-25 1944-10-25 Fluorescent material

Publications (1)

Publication Number Publication Date
US2417038A true US2417038A (en) 1947-03-04

Family

ID=24237405

Family Applications (1)

Application Number Title Priority Date Filing Date
US560344A Expired - Lifetime US2417038A (en) 1944-10-25 1944-10-25 Fluorescent material

Country Status (1)

Country Link
US (1) US2417038A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563900A (en) * 1947-06-21 1951-08-14 Westinghouse Electric Corp Phosphor and method of making
US2563901A (en) * 1948-05-15 1951-08-14 Westinghouse Electric Corp Phosphor and method of making

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB492722A (en) * 1937-03-24 1938-09-26 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Improvements in luminescent materials
GB492735A (en) * 1935-12-23 1938-09-26 Jakob Nussbaum Improvements in luminous compositions and methods of manufacturing the same
GB512154A (en) * 1938-03-11 1939-08-30 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Improvements in luminescent materials
US2179134A (en) * 1936-11-18 1939-11-07 Etude & L Expl Des Matieres Lu Inorganic luminous material
US2226407A (en) * 1938-03-16 1940-12-24 Gen Electric Luminescent material
DE703014C (en) * 1937-03-20 1941-02-26 Patra Patent Treuhand Fluorescent

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB492735A (en) * 1935-12-23 1938-09-26 Jakob Nussbaum Improvements in luminous compositions and methods of manufacturing the same
US2179134A (en) * 1936-11-18 1939-11-07 Etude & L Expl Des Matieres Lu Inorganic luminous material
DE703014C (en) * 1937-03-20 1941-02-26 Patra Patent Treuhand Fluorescent
GB492722A (en) * 1937-03-24 1938-09-26 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Improvements in luminescent materials
GB512154A (en) * 1938-03-11 1939-08-30 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Improvements in luminescent materials
US2226407A (en) * 1938-03-16 1940-12-24 Gen Electric Luminescent material

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563900A (en) * 1947-06-21 1951-08-14 Westinghouse Electric Corp Phosphor and method of making
US2563901A (en) * 1948-05-15 1951-08-14 Westinghouse Electric Corp Phosphor and method of making

Similar Documents

Publication Publication Date Title
US3294699A (en) Luminescent europium activated strontium aluminate
US2542336A (en) Titanium activated magnesium orthostannate
US2408475A (en) Fluorescent zinc oxide
US2417038A (en) Fluorescent material
US2554999A (en) Zinc silicate phosphor
US2447210A (en) Erythemal phosphor
US2664401A (en) Alkaline earth phosphate phosphors of the apatite type
US3544483A (en) Europium activated strontium magnesium orthophosphate phosphors
US3599028A (en) Mercury vapor discharge lamp employing europium activated calcium and/or strontium pyrophosphate luminescent material
US2312266A (en) Fluorescent material and process of making same
GB578272A (en) Improvements in luminescent materials
US2499307A (en) Barium di-silicate phosphor
US2596509A (en) Titanium activated barium pyrophosphate phosphor
US2474193A (en) Calcium silicate phosphor
US2245414A (en) Fluorescent material
US3430089A (en) Calcium halophosphate phosphors
US2482450A (en) Barium halophosphate phosphor
US3965031A (en) Red emitting phosphors
US2846403A (en) Lead activated barium zinc silicate phosphor
US2668148A (en) Thallium activated calcium phosphate phosphor containing aluminum
US2312268A (en) Fluorescent material
US2455414A (en) Aluminum phosphate phosphor
US2975143A (en) Method of producing ultraviolet luminescing silicates
US2901647A (en) Discharge lamp and phosphor
US2179134A (en) Inorganic luminous material